Creation of spin-triplet Cooper pairs in the absence of magnetic ordering

Abstract

In superconducting spintronics, it is essential to generate spin-triplet Cooper pairs on demand. Up to now, proposals to do so concentrate on hybrid structures in which a superconductor (SC) is combined with a magnetically ordered material (or an external magnetic field). We, instead, identify a novel way to create and isolate spin-triplet Cooper pairs in the absence of any magnetic ordering. This achievement is only possible because we drive a system with strong spin-orbit interaction--the Dirac surface states of a strong topological insulator (TI)--out of equilibrium. In particular, we consider a bipolar TI-SC-TI junction, where the electrochemical potentials in the outer leads differ in their overall sign. As a result, we find that nonlocal singlet pairing across the junction is completely suppressed for any excitation energy. Hence, this junction acts as a perfect spin triplet filter across the SC generating equal-spin Cooper pairs via crossed Andreev reflection.

12 pages, 8 figures

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Cited by in corpus (20)

• Theory of Majorana zero modes in unconventional superconductors
• Anisotropic proximity-induced superconductivity and edge supercurrent in Kagome metal, K1-xV3Sb5
• Formation and detection of Majorana modes in quantum spin Hall trenches
• Crossed Andreev reflection in spin-polarized chiral edge states due to the Meissner effect
• Superconducting proximity effect in $d$-wave cuprate/ graphene heterostructures
• Influence of a chiral chemical potential on Weyl hybrid junctions
• Exciting odd frequency equal-spin-triplet correlations at metal-superconductor interfaces
• Crossed Andreev reflection in topological insulator nanowire T-junctions
• Edge-induced pairing states in a Josephson junction through a spin-polarized quantum anomalous Hall insulator
• A generic model with unconventional Rashba bands and giant spin galvanic effect
• Directional electron-filtering at a superconductor-semiconductor interface
• Odd-frequency superconducting pairing due to multiple Majorana edge modes in driven topological superconductors
• Andreev spectroscopy of nonhelical spin textures in topological insulators
• Backscattering off a driven Rashba impurity at the helical edge
• Spin-resolved spectroscopy of helical Andreev bound states
• Odd-frequency pairs and anomalous proximity effect in nematic and chiral states of superconducting topological insulators
• Effects of the Vertices on the Topological Bound States in a Quasicrystalline Topological Insulator
• Anomalous flux periodicity in proximitised quantum spin Hall constrictions
• Spin-Valley Locking and Pure Spin-Triplet Superconductivity in Noncollinear Antiferromagnets Proximitized to Conventional Superconductors
• Odd-frequency Pairing in Josephson Junctions Coupled by Magnetic Textures